/*
 * Copyright (c) 2013, SRI International
 * All rights reserved.
 * Licensed under the The BSD 3-Clause License;
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 * 
 * http://opensource.org/licenses/BSD-3-Clause
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 * Redistributions of source code must retain the above copyright
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package com.sri.ai.grinder.plaindpll.api;

import com.google.common.annotations.Beta;
import com.google.common.base.Function;
import com.sri.ai.expresso.api.Expression;
import com.sri.ai.grinder.api.RewritingProcess;

@Beta
public interface TermTheory {
	
	/**
	 * Indicates whether expression is a term according to this term constraintTheory.
	 * @param expression
	 * @param process
	 * @return
	 */
	boolean isTerm(Expression expression, RewritingProcess process);
	
	/**
	 * Indicates whether expression is a generalized variable term according to this term constraintTheory.
	 * @param expression
	 * @param process
	 * @return
	 */
	boolean isVariableTerm(Expression expression, RewritingProcess process);
	
	/**
	 * Indicates whether equalities between two terms may imply further facts in this theoryWithEquality.
	 */
	boolean equalityBetweenTermsImpliesFurtherFacts();
	
	/**
	 * Indicates whether disequalities between two terms may imply further facts in this theoryWithEquality.
	 */
	boolean disequalityBetweenTermsImpliesFurtherFacts();
	
	Expression getSplitterTowardDisunifyingDistinctTerms(Expression term, Expression anotherTerm, RewritingProcess process);
	
	/**
	 * Rewrites a term used in a term so that it uses only equality equivalence class representatives when possible.
	 * For example, if a constraint involves X = Y and p(X) = q(X) and p(Y) = c
	 * we want to normalize it to X = Y and q(Y) = p(Y) = c.
	 * X is replaced by its representative in p(X) and q(X), but not in X = Y itself since that would incorrectly remove the equality X = Y.
	 * @param term
	 * @param constraint
	 * @param process
	 * @return
	 */
	Expression normalizeTermModuloRepresentatives(Expression term, Function<Expression, Expression> getRepresentative, RewritingProcess process);

	/**
	 * Indicates whether terms have no arguments.
	 * This permits skipping the updating of representatives in bindings maps.
	 * @return
	 */
	boolean termsHaveNoArguments();
}